Telephone system.



W. A. FRIGKH TELEPHONE SYSTEM.

APPLIOATION FILED MAR.26, 1912.

Patented Feb. 24, 1914.

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ran STATES PATENT OFFICE.

WILLIAM A. FBIGKE, OF CHICAGO, ILLINOIS, ASSIGNOR TO MONARCH TELEPHONE MANUFACTURING COMPANY, OF FORT DODGE, IOWA, A CORPORATION OF IOWA.

TELEPHONE SYSTEM.

Specification of Letters Patent.

Patented Feb. 24:, 1914:.

Application filed March 26, 1912. Serial No. 686,387.

To all whom it may concern Be it known that I, WILLIAM A. Fnroxn, citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a-certain new and useful Improvement in Telephone Systems, of which the following is a full, clear, concise, and exact description, reference being had to the accompanying drawings, forming a part of this specification.

My invention relates to common battery multiple switch board systems and has for its object the simplification of line equipment and cord circuit equipment and also has for its object the provision of improved means for preventing the manifestation of false busy tests.

My invention is of such a nature that it can best be understood by a description of the preferred embodiment thereof shown in the accompanying drawing, but to which embodiment I do not limit myself.

The drawing shows two telephone lines and exchange apparatus for connecting the same.

Like parts are indicated by similar characters of reference.

Two metallic telephone lines are illustrated as extending from stations A B to the exchange, at which exchange the lines terminate in answering jacks 1 and are connected with multiple jacks 2, all as is well understood by those skilled in the art. The equipment at each of the substations A B includes the well known telephone. switch hook 3 having one contact which is engaged by the switch hook when relieved of the weight of the telephone receiver 4 whereby the normally metallically disconnected sides of the line at each substation are metallically connected by way of a transmitter 5 and the receiver 4. A signal bell 6 is included in bridge of the line at each of the substations, the bridge conductor that contains the bell also including a condenser 7 for the purpose of enabling alternating current to pass through the bell for its operation while at the same time preventing the passage of current from the common battery 8 at the exchange through the bell bridge. hen the receiver is removed from the switch hook at a calling station, circuit through the common battery is completed by way of the.

switch hook, as described, this circuit including the winding of the line relay 9 individual to the calling line. When circuit through the line relay 9 of the calling line is thus established, the armature of said line relay is attracted to close a local circuit through a line lamp 10 or other line indicator, which local circuit may be traced from the positive pole of the common battery 8 through the armature of the cutoff relay 11, the lower contact normally engaging said armature, the .attracted armature of the line relay 9, the contact then engaged by said armature, line lamp 10, to the negative pole of the common battery 8. The operator responds by inserting the answering plug 12 into the thimble of the answering jack to which the signal device 10 responds. The

tip of the inserted answering plug 12 engages the tip spring of the answering jack 1 and the sleeve of the answering plug 12 engages the sleeve spring of the answering ]2LC The sleeve of the inserted answering plug 12, by engaging the thimble and sleeve spring of the answering jack, establishes a connection for closing circuit through the cutofi relay 11 and to connect another pole of the battery 8 with the thimble of the answering jack and the thimbles of the associated multiple, jacks that are connected with the aforesaid thimble, whereby these thimbles, which are normally connected with the positive pole of the battery, are, during the insertion of the answering plug, connected with both terminals of the battery. The circuit established for the cutoff relay is traceable from the positive pole of the common battery 8 through the winding of the cutoff relay, the thimble of the answering jack, the sleeve of the inserted answering jack, the sleeve spring of the answering jack, the winding of the line relay 9 of the calling line to the negative pole of the common battery. The armature of the cutoff relay 11 operates to open the circuit of the line lamp 10 at the lower contact of such armature. The upper contact of the armature of the cutoff relay 11 is in open circuit when the cutoff relay is energized so that the positive pole of the common battery may be disconnected from the tip side of the line, such positive pole of the common battery 1 having a substitute connection with the tip side of the line by way of the winding of the designed to control the circuit connections of the called line just as the answering plug 12 controls the circuit connections of the calling line, it of course being understood that the cutotl relay of the called line is energized before the called subscriber responds so that the cutoff relay of the called line acts to prevent the called subscriber from operating his line indicator 10 rather than to restore such line indicator to its normal condition which would be done in the case of a calling line.

Like parts in both line equipments are given similar characters of reference, similarly designated parts having similar functions.

The tip and the sleeve line springs and the thimbles of each of the multiple jacks are in multiple with the tip and sleeve line springs and thimbles, respectively, of the associate answering jack so that a plug inserted in any of the multiple jacks will serve to connectthe sleeve or thimble of such jack and the sleeve line spring of such jack whereby the plugs inserted within any multiple jack will cause the'same circuit changes in the line equipment that are occasioned when such plugs are inserted in the answering jacks. When the connecting plug 14 is inserted in a multiple jack, the positive pole of the battery 8 has its normal connection with the tip side of the called line broken, this pole of the battery 8 then having a substitute connection with the tip side of the called line by way of the called subscribers supervisory relay 15, the winding of this relay having one terminal that is connected with the tip of the connecting plug by way of normally engaged contacts 16 of the operators listening key and the normally engaged contacts 17 of the operators ringing key. Condensers 18 and 19 are included, respectively, in the tip and sleeve sides of the cord circuit to enable the employment of two supervisory relays or disconnect magnets 13 and 15 which shall be individual to the answering and connecting ends of the cord circuit and shall be within the control of the calling and called subscribers when the answering and connecting plugs are in engagement with the spring jacks of the calling and called subscribers lines.

The usual calling and called clearing out or supervisory signal lamps 20 are individually controlled by the supervisory relays 13 and 15, these supervisory signals each having a local circuit which is partially established by the sleeve of the associate plug and the sleeve spring of the jack receiving the plug, such circuit being completed by way of the armature of the associate supervisory relay when such armature is unattra-cted, thearmature being unattracted when the associate supervisory relay is included in open circuit upon the replacement of the telephone at the associated substation upon its switch hook, in the case of calling a subscriber, the supervisory relay corresponding to the called subscriber remaining deenergized until the called subscribers receiver is removed from its switch hook and being again deenergized when such called subscribers receiver is restored upon its switch hook. The supervisory signals, so far as their signaling functions are concerned, are similar to those which are well known. The circuit for each of the supervisory signals 20 may be traced from the positive pole of the common battery 8, through the armature (when unattracted) of the associate supervisory relay, the signal 20 itself, the sleeve of the associate plug, the sleeve spring of the jack receiving such plug, the winding of the line relay 9, to the positive pole of the common battery,

When a twenty-four volt common battery is employed, the line relays may be wound to one hundred ohms resistance each, the cutoff relays may be wound to five hundred ohms resistance each, and the supervisory relays may be wound to one hundred ohms re sistance each. By the equipment illustrated, the line relays or magnets are not excluded from circuit at any time, current being fed from the battery 8 to one side of the line by way of the line relay and to the other side of the line by way of the supervisory relay that has become associated with the line by the associate plug, the battery thus being located between the line relay and such associate supervisory relay, these two relays serving to balance the line so far as the supply of battery current to the line is concerned, without the aid of cord circuit equipment to perform the function of the line relays 9.

By permanently connecting each line relay between one side of the line and the common battery, and oining the ack spring connected with this side of the line with the jack thimble by means of the sleeve of the inserted plug and constituting this jack thimble a terminal of the associate cutoff relay, I am enabled to open and close the circuit of such cutoif relay through the winding of the associate line relay whereby a part of the line equipment is used for the local circuit for the cutoff relay. The connected thimbles or contacts are normally connected with the positive pole of the battery but are also brought into connection with the negative pole of the battery when a plug is inserted, the negative pole of the battery being then connected with the thimbles by way of the associate line relay and the sleeve spring of the jack engaging the sleeve of the inserted plug. The test circuit may be partially traced from the positive pole of the battery through the right hand impedance coil 21, the o-perators head telephone 22-, the secondary 23 of the operators telephone outfit, the alternate contact 24 of the operators listening key, the tip side of the cord circuit then connected with the alternate contact 24, the tip of the testing plug which is the connecting plug 14:, to the thimble of the tested jack. If no jack that is in association with the tested jack holds a plug then there will be no busy test manifestation since the tested thimble would then have connection alone with the positive pole of the battery. If, however, a jack in association with the tested jack did hold a plug, then the tested thimble would be connected with the negative pole of the battery by way of the sleeve of the plug inserted in the associated jack, in which event the operator would secure an audible busy test manifestation in her head telephone, the busy test circuit which was above partially traced then being continued from the thimble of the tested jack to the thimble of the jack holding the plug, thence by way of the sleeve of such inserted plug to the sleeve spring of the jack holding such inserted plug to the negative pole of the battery by way of the line relay.

To prevent the relay 15 associated with the testing plug from operating during the testing process and to prevent false tests, the circuits of the called supervisory relay and called supervisory lamp include the normal contacts of the o-perators listening key. \Vhen the operator has depressed her listening key, she disconnects these normal contacts so that the connection of the called supervisory relay with the tip strand and the connection of the called supervisory lamp with the sleeve strand are broken. The operators telephone equipment is thus associated with the connecting end of the cord circuit to the exclusion of the answering end of the cord circuit and all supervisory signal apparatus during the testing operation. By connecting the called supervisory lamp with the sleeve strand of the cord circuit by way of a normal listening key contact, the supervisory lamps of other cords cannot be caused to glow when the listening keys associated therewithare depressed.

The calledsubscribers supervisory relay has a double or multiple connection with the tip strand of the link circuit, one connection being by way of the upper normal contact of the listening or testing key or switch and the other by way of a contact which it engages by the armature of the relay when said relay is energized. After the relay has been energized the operator cannot deenergize the same when testing or listening owing to the alternate path established for the relay by way of its armature and the then engaged contact. The control which the called subscriber has over his relay 15 is not disturbed.

While I have herein shown and particularly described the preferred embodiment of my invention, I do not wish to be limited to the precise details of construction and circuit arrangement shown as changes may be made without departing from the spirit of my invention.

Having thus described my invention, I claim as new and desire to secure by Letters Patent the following A multiple switch board system including telephone lines extending from substations to an exchange; a link circuit at the eX- change for uniting lines in conversation; clearing out or supervisory apparatus in cluding a relay and a signal device whose circuit is governed by the relay; an operators testing outfit; and an operators testing switch or key, said switch or key having a normal contact through which the relay is connected with one side of the link circuit, said relay having a contact that is in multiple with the aforesaid normal contact of the operators key or switch and another contact which is in connection with that side of the link circuit with which the relay is connected by said normal contact, these two contacts serving to establish an alternate path for said relay when the relay is energized so that the relay may not be deenergized by the mere operation of the operators test-ing key or switch.

In witness whereof, I hereunto subscribe my name this 29th day of February A. D.,

WILLIAM A. FRICKE. Witnesses:

G. L. CRAGG, E. L. WHITE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patent! Washington, D. G. 

